 /*
  * $Header: /cvshome/build/org.osgi.service.log/src/org/osgi/service/log/LogService.java,v 1.9 2006/06/16 16:31:49 hargrave Exp $
  *
  * Copyright (c) OSGi Alliance (2000, 2006). All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  * http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 package org.osgi.service.log;

 import org.osgi.framework.ServiceReference;

 /**
  * Provides methods for bundles to write messages to the log.
  *
  * <p>
  * <code>LogService</code> methods are provided to log messages; optionally with a
  * <code>ServiceReference</code> object or an exception.
  *
  * <p>
  * Bundles must log messages in the OSGi environment with a severity level
  * according to the following hierarchy:
  * <ol>
  * <li>{@link #LOG_ERROR}
  * <li>{@link #LOG_WARNING}
  * <li>{@link #LOG_INFO}
  * <li>{@link #LOG_DEBUG}
  * </ol>
  *
  * @version $Revision: 1.9 $
  */
 public interface LogService {
     /**
      * An error message (Value 1).
      *
      * <p>
      * This log entry indicates the bundle or service may not be functional.
      */
     public static final int LOG_ERROR = 1;
     /**
      * A warning message (Value 2).
      *
      * <p>
      * This log entry indicates a bundle or service is still functioning but may
      * experience problems in the future because of the warning condition.
      */
     public static final int LOG_WARNING = 2;
     /**
      * An informational message (Value 3).
      *
      * <p>
      * This log entry may be the result of any change in the bundle or service
      * and does not indicate a problem.
      */
     public static final int LOG_INFO = 3;
     /**
      * A debugging message (Value 4).
      *
      * <p>
      * This log entry is used for problem determination and may be irrelevant to
      * anyone but the bundle developer.
      */
     public static final int LOG_DEBUG = 4;

     /**
      * Logs a message.
      *
      * <p>
      * The <code>ServiceReference</code> field and the <code>Throwable</code> field
      * of the <code>LogEntry</code> object will be set to <code>null</code>.
      *
      * @param level The severity of the message. This should be one of the
      * defined log levels but may be any integer that is interpreted in a
      * user defined way.
      * @param message Human readable string describing the condition or
      * <code>null</code>.
      * @see #LOG_ERROR
      * @see #LOG_WARNING
      * @see #LOG_INFO
      * @see #LOG_DEBUG
      */
     public void log(int level, String message);

     /**
      * Logs a message with an exception.
      *
      * <p>
      * The <code>ServiceReference</code> field of the <code>LogEntry</code> object
      * will be set to <code>null</code>.
      *
      * @param level The severity of the message. This should be one of the
      * defined log levels but may be any integer that is interpreted in a
      * user defined way.
      * @param message The human readable string describing the condition or
      * <code>null</code>.
      * @param exception The exception that reflects the condition or
      * <code>null</code>.
      * @see #LOG_ERROR
      * @see #LOG_WARNING
      * @see #LOG_INFO
      * @see #LOG_DEBUG
      */
     public void log(int level, String message, Throwable exception);

     /**
      * Logs a message associated with a specific <code>ServiceReference</code>
      * object.
      *
      * <p>
      * The <code>Throwable</code> field of the <code>LogEntry</code> will be set to
      * <code>null</code>.
      *
      * @param sr The <code>ServiceReference</code> object of the service that this
      * message is associated with or <code>null</code>.
      * @param level The severity of the message. This should be one of the
      * defined log levels but may be any integer that is interpreted in a
      * user defined way.
      * @param message Human readable string describing the condition or
      * <code>null</code>.
      * @see #LOG_ERROR
      * @see #LOG_WARNING
      * @see #LOG_INFO
      * @see #LOG_DEBUG
      */
     public void log(ServiceReference sr, int level, String message);

     /**
      * Logs a message with an exception associated and a
      * <code>ServiceReference</code> object.
      *
      * @param sr The <code>ServiceReference</code> object of the service that this
      * message is associated with.
      * @param level The severity of the message. This should be one of the
      * defined log levels but may be any integer that is interpreted in a
      * user defined way.
      * @param message Human readable string describing the condition or
      * <code>null</code>.
      * @param exception The exception that reflects the condition or
      * <code>null</code>.
      * @see #LOG_ERROR
      * @see #LOG_WARNING
      * @see #LOG_INFO
      * @see #LOG_DEBUG
      */
     public void log(ServiceReference sr, int level, String message,
             Throwable exception);
 }

